Of carboxylic acid amides

Many procedures for the formation of carboxylic acid amides are known in the literature. The most widely practiced method employs carboxylic acid chlorides as the electrophiles which react with the amine in the presence of an acid scavenger. Despite its wide scope, this protocol suffers from several drawbacks. Most notable are the limited stability of many acid chlorides and the need for hazardous reagents for their preparation (thionyl chloride, oxalyl chloride, phosgene etc.) which release corrosive and volatile by-products. Moreover, almost any other functional group in either reaction partner needs to be protected to ensure chemoselective amide formation.2 The procedure outlined above presents a convenient and catalytic alternative to this standard protocol. 

This procedure describes the use of pseudoephedrine as a chiral auxiliary for the asymmetric alkylation of carboxylic acid amides. In addition to the low cost and availability in bulk of both enantiomeric forms of the chiral auxiliary, pseudoephedrine, a particular advantage of the method is the facility with which the pseudoephedrine amides are formed. In the case of carboxylic acid anhydrides, the acylation reaction occurs rapidly upon mixing with pseudoephedrine. Because pseudoephedrine amides are frequently crystalline materials, the acylation products are often isolated directly by crystallization, as illustrated in the procedure above. 

The hydrolyses of carboxylic acid amides, RCONR R", are catalysed by both acids and bases, and generally do not take place in neutral media. Ost-wald176 made the first quantitative measurements of the catalytic activity of... 

The Influence of Fluoro Substituents On the Reactivity of Carboxylic Acids, Amides, and Peptides in Enzyme-Catalyzed Reactions ... 

This latter thought has an important consequence if compounds with C=0 double bonds are sorted in decreasing order of resonance stabilization of their C=0 group they are at the same time sorted according to their increasing propensity to enolization. So as the resonance stabilization of the C=0 double bond decreases from 22 kcal/mol to somewhere near zero in the order carboxylic acid amide > carboxylic acid ester/carboxylic acid > ketone > aldehyde > carboxylic acid chloride/-bromide, the enol content increases in this same order (Figure 12.2). These circumstances immediately explain why no enol reactions whatsoever are known of carboxylic acid amides, virtually none of normal carboxylic acid esters/carboxylic acids, but are commonly encountered with ketones, aldehydes and carboxylic acid halides. 

The 36C1 exchanges between gaseous H 36C1 and adducts of carboxylic acid amides with phosphoryl chloride have also been studied291. 

C-OH- -0= NH- -0=C C CNDO/2 for charges. Used Lennard-Jones 9-6-1 and 12-6-1. No Morse function. Tfested on crystal structures of carboxylic acids, amides [338, 339]... 

The application of lactams in heterocyclic synthesis depends on the activation of their amide function.5 Similar activation of other functional groups, e.g., the conversion of ketones to enamines6 and of carboxylic acid amides to imino ethers,7 presented new applications for these compounds. Similarly, the conversion of lactams into lactim ethers offers a greater scope for the use of lactams in organic synthesis. 

According to Bredereck et al.,17,18 the reaction of carboxylic acid amides with dialkyl sulfates proceeds via the intermediate ambident cation such as (5). In the case of caprolactam, when excess dialkyl sulfate is taken, the A,(9-dialkyl derivative (6) is formed, which with base forms 3 (Scheme 1). 

From formylation reactions of CH-acidic compounds, which take place if mixtures of carboxylic acid amides and anhydrides are used as formylating agents, it was concluded that the latter compounds form similar adducts to those from amides and acid halides. ... 

Wallach was the first (1874) to report on the transformation of carboxylic acid amides to amide chlorides by treatment with PCls " various types of amides were converted by this reagent to chloromethyleneiminium chlorides (30 equation 5j(jg reactions can include the a-chlorination of... 

The addition of alcohols to nitrilium salts gives rise to formation of alkoxymethyleneiminium salts, which react with bases to yield imido esters (231 Scheme 33). - By deprotonation of carboxylic acid amides ambident anions are formed, which can be alkylated in the presence of silver ions to give imido esters, e.g. (232). " Secondary amides react with trifluoroacetic acid anhydride or trifluorosulfonic acid anhydride to give mixed anhydrides of imidic acids (233). ... 

Not least of all, the reduction of carboxyl derivatives on the ends or side walls of carbon nanotubes is rather easy to achieve. The reduction of carboxylic acid amides (e.g., of the didecyl amide) on the side wall of MWNT with lithium aluminum hydride yields aminoalkylated nanotubes with the tubular structure not being affected by the reaction. 

Substitution of carboxylic acid amides. via carboxylic acid hydroxymethylamides... 

Partial hydrolysis of carboxylic acid amides Sulfonamidocarboxylic acids... 

Pisaniello and Lincoln have made detailed H NMR studies of the amide complexes [ScLs][C104]3 in CD3CN and CDjNOj. With NMF, DMF, A,A-diethylformamide and A,iV-dibutylformamide, exchange between free and bound ligand occurred in the fast exchange limit at all accessible Table 4 Effect of Coordination on Stretching Wavenumbers of Carboxylic Acid Amides ... 

Similarly to the release of carboxylic acids, amides have been grouped according to acidic and photochemically cleavable linkers (Table 1.7.2)... 

The reaction of carboxylic acid amides with phosphorus pentachloride, to yield compounds I and II, was investigated extensively by Wallach and his students in 1876-1882, and later by v. Braun, who utilized this reaction to degrade secondary amines to ammonia. The highly reactive imidoyl chlorides have been used, especially by v. Braun, as synthetic tools to produce a variety of compounds which could not easily be synthesized by other procedures. However, imidoyl chlorides never made the headlines in synthetic organic chemistry, most likely because of the inherent difficulty involved in handling these highly reactive compounds. 

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